The results for FWI and the source-focusing WRI method of [1]} are presented in Figure REF , which clearly shows the inability of FWI to converge to the true model. For the source-focusing WRI (equation REF ), the source covariance is defined as a diagonal matrix \(\Sigma _{\mathrm {q}}=\mathrm {diag}(\mathbf {\sigma }^2)\) . The variance function \(\mathbf {\sigma }\)  is spatially and source-position dependent, e.g.:
\(\Sigma _{\mathrm {q}}=\mathrm {diag}(\mathbf {\sigma }^2),\quad \mathbf {\sigma }^2(\mathbf {x};\mathbf {x}_{\mathrm {s}})=(\left\Vert \mathbf {x}-\mathbf {x}_{\mathrm {s}}\right\Vert ^2+\delta ^2)^{-1}.\) 
